The present invention is directed to a device for inserting a small amount of a rare earth containing mixture or composition into a combustion chamber, particularly the combustion chamber of an internal combustion engine with spark ignition or compression ignition.
Such a device is known from DE-A 29 32 603. In the known device a rare earth metal composition finely dispersed in an aqueous solution is inserted in the air intake manifold of an internal combustion engine.
The problem underlying the invention is to provide a device of simple design and structure, by which a rare earth mixture or composition may be continuously introduced in small amounts during a long operation period without or with minimum of maintenance on the combustion chamber of an internal combustion engine.
The present invention includes a container, which has an air-permeable dry filling of rare earth fibers and/or rare earth powder, that communicates via an opening with the atmosphere, and that communicates via a suction connection or line with either a vacuum line, or directly with the combustion chamber of the engine.
Preferably the opening to the atmosphere is formed by one end of a tube, which communicates with the filling via at least one orifice, wherein an air filter may be arranged within the tube adjacent the opening and wherein a throttle is arranged downstream of the air filter within the tube.
In a device of the invention a pressure below the atmospheric pressure is induced by means of the vacuum line into the tube. Thereby air is sucked from the container via the orifice, which conveys a small amount of particles of the filling via the tube and the vacuum line into the combustion chamber.
A filter, which may be arranged in the flow-path between the orifice and the filling, acts as a flowbarrier to finely divide the particles to be sucked into the tube and to thereby determine an enlarged surface,--the filter surface facing the filling--for sucking in the particles into the tube. This avoids undue localizing and the risk of clogging. The filter is preferably formed as a filter screen in a cylindrical shape which is arranged transversely to the tube and communicates with its one end or "foot" with the orifice in the tube.
The container may be dimensioned for a filling which is sufficient for the whole lifetime of the internal combustion engine. Alternatively, as the space in modern automobiles is limited, a container dimensioned for a filling sufficient for a restricted operation time, e.g. corresponding to 80,000 km running distance for a passenger car, may be installed.
The container may be arranged removably in the engine compartment of an automobile to be exchanged against a fresh container in the latter case. The container may also have a refilling opening for renewal of the filling.
The device of the invention enables to add a small amount of a rare earth mixture or composition in a dry state to the air intake of an internal combustion engine avoiding the carrying and filling of a solvent, thereby avoiding the necessity of regularly refilling solvent after short time periods and/or additional space necessary for a solvent container in the automobile.
The filling is preferably in fibrous and/or powder form. The following two viewpoints should govern the selection of the filing to be used in the invention:
1. The particle size of the materials ranges from 0.25 mm (60 mesh) down to as low as 0.5 micron, with the size of 0.048 mm (300 mesh) representing a preferred size. PA1 2. In even more general terms, it should be understood that the used compositions should contain a percentage of cerium (Ce O.sub.2) as high as can readily and economically be achieved, this in view, of course, of the practical difficulties involved in separating the various rare earth oxides.
Principally the cerium content, by weight in the mixture varies from 30% up to practically 100%. Three examples for preferred compositions are given in the following specific description.
By introducing a small amount of the mixture into the air intake, the harmful pollutants, particularly that of CO, CO.sub.2, HC and NO.sub.x are reduced, and the combustion is improved so that an effect comparable to that of a controlled catalytic converter is achieved, but at much less expenditure.
It is an important advantage of a device of the invention that it can be fitted to existing automobiles even when driven by engines using unleaded fuel. Of course, the device may be used in engines driven by any other conventional fuels for internal combustion engines.
The vacuum line might be the intake manifold of the engine. It is, however, also possible to directly connect the suction line with the combustion chamber. In that case a check valve must be provided in order to ensure, that the container communicates with the combustion chamber solely during the intake period of the engine.
The device of the invention may likewise be applied in spark ignition or compression ignition engines and also in stationary internal combustion engines.
Particularly in applications for large combustion engines, like locomotive- ship- or stationary engines it is preferred to transport the rare earth particles by a motor-driven conveying means in the vicinity of a suction opening of the suction line.